This invention relates to a method of detecting cows which are on-heat, and apparatus therefor.
Milking cows are generally kept pregnant every year to maintain lactation. In winter, the cows are kept in sheds. A cow""s ovulation cycle is about three weeks, and it is obviously important for insemination to catch the cow at the right point of her cycle.
When a cow is on-heat, she will for a brief period allow herself to be mounted by another cow, similar to acceptance of a bull. The mounting is therefore a clear indication to the farmer that the cow is ready for insemination. However, the infrequency and short duration (usually only a few seconds) of mounting are such that the mounting will rarely coincide with the visits of the farmer to the cow shed. A farmer cannot stand and wait all day for such occurrences.
Two prior suggested methods of detection involve either pressure sensors on the cow""s rear, or a pressure sensor on the cow""s feet or on the floor to measure activity or weight differences. However, ordinary scratching by a cow of its rear can activate the first type of sensor, and in a cow shed with tens or hundreds of cows, there is always significant movement of the cows causing constant activity and weight differences.
According to one aspect of the present invention, there is provided a method of detecting a first cow when mounted by a second cow wherein one or more beams of light are directed wholly or substantially horizontally at one or more detectors, and at a level above the first cow and corresponding to the additional height of the second cow when mounting the first cow, such that the mounting of the first cow by the second cow breaks one or more of the beams of light to one or more of the detectors, and the or each detected break causes activation of an alarm means or a cow identification means or both.
Thus the present invention provides an automatic method of alerting when a cow on heat, and/or of immediately identifying a cow on heat, which is only activated as and when the cow allows herself to be mounted. The alarm means and the cow identification means could be used together either simultaneously or independently.
Any form or source of light capable of being focused along a beam could be used. Suitable forms of light beams include a laser and a light emitting diode period
Where a single beam of light is used, the beam may be stationary but pass over a relevant area above the cows. Preferably the light beam scans an area, more preferably by rotation. The beam may be rotating constantly in one direction, or reversibly rotating across a sector.
Where a plurality of light beams are used, the beams may again be stationery, and arranged in parallel or in two or more different directions across a relevant area. Alternatively, each light beam is rotating.
A plurality of light beams whose paths overlap, either simultaneously or intermittently, further provides directional information on the location of the relevant cows. Any breaks in two or more of the beams caused by one mounting event may not occur simultaneously, especially if the beams are rotating. However, the multiple beam breakage should still occur contemporaneously for the same mounting event, so that locational information on the relevant cows is still achievable.
The or each beam of light may also be transmitted constantly or intermittently, e.g. pulsed. The frequencies of two or more beams of light may also be different to assist detection of which beam or beams are being broken by one detector or neighbouring detectors, possibly using matched frequency detectors.
The or each detector may be located remote from the source(s) of light. Any means for detecting the receipt of a beam of light is suitable, e.g. a photodiode. The or each detector could be dedicated, unidirectional and/or be designed to receive only one light frequency, or be of a more general nature. Alternatively, the or each beam of light is reflected by one or more reflective means to one or more detectors. Such detector(s) could again be remote from the or each source of light, or could be near or adjacent to the light source(s), possible within the same housing. The reflective means could be discrete or continuous, and could comprise one or more mirrors, or be a retroreflective strip or series of discs able to reflect light directly back independent of the angle of incidence.
The alarm means could be an audio, visual or electronic signal adapted to alert a farmer of mounting activity, to which he can then respond by visiting the cow shed. Preferably, the invention uses a cow identification means. The means for identifying the cow on-heat could be an active or passive means, i.e. a means able to mark the first cow or provide a mark able to identify the first cow for subsequent detection by the farmer, or a means of remotely identifying the cow, e.g. on one or more cameras. The first cow could be identified from its freeze-brand or other normally applied marking, or be marked with an additional preferably photogenic identifying mark such as video coding. The identification means may also be able to identify the second mounting cow, if desired or necessary.
The identification means could be located remotely from the or each light beam or the or each detector, or alternatively near or adjacent thereto. Using one or more directable cameras as the identification means, such cameras generally having different locations, should increase the chances of positive identification of the relevant first cow. Different identification means could be connected to different light beams. Alternatively, the locational information from all the detected broken light beams could be centrally processed to singularly focus the, some or all of the identification means towards the calculated mounting location.
According to one preferred embodiment of the present invention, two or more beams of light and two or more detectors are used, and the detectors work in partnership to co-ordinate two or more differently located cameras to the location of breakage of the light beams.
According to a second aspect of the present invention, there is provided an apparatus for detecting a first cow when mounted by a second cow, comprising one or more beams of light, one or more light detectors, and an alarm means or a cow identification means, wherein the or each beam of light is directed wholly or substantially horizontally at one or more detectors at a level above the first cow and corresponding to the additional height of the second cow when mounting the first cow, such that the mounting of the first cow by the second cow breaks one or more of the beams of light, and the or each detected break causes activation of the alarm means or cow identification means or both.
The present invention could be used in relation to one cow to be detected, or simultaneously for a small or large number of cows. The relevant cows could be particularly targeted, and possibly have their freedom of movement limited, or they could be allowed to roam over the area covered by the light beam(s) and detector(s). To cover a large number of cows, a number of light beams and detectors are preferred to cover the relevant area.
According to a third aspect of the present invention, there is provided a method of detecting a first cow when mounted by a second cow wherein a passive sensor is directed wholly or substantially horizontally a level above the first cow and corresponding to the additional height of the second cow when mounting the first cow, such that the mounting of the first cow by the second cow activates the sensor by altering the field of detection, and the sensor causes activation of an alarm means or a cow identification means or both.
The passive sensor could be a passive infra-red sensor, similar to those commonly used in room and outside security systems which activate on movement within the field of detection.
The present invention is applicable to all cows, whether they be dairy cows, beef cows or otherwise. It is equally applicable to other farm animals, such as pigs, which are bred or inseminated in a similar manner.